Phasing tool



Sept. 12,.1967 w..v. CARNEY ETAL 3,340,752

PHASING TOOL Filed Dec. 28, 1965 2 Sheets-Sheet 1 INVENTORS, W/lL/AM V-CARA/E) PAUL K DeLZ/CA ATTORNEY P 12, 1967 w. v. CARNEY ETAL 3,340,752

PHASING TOOL 2 Sheets-Sheet 2 Filed Dec. 28, 1965 INVENTORS. y /L AM 1CARA/E f A1514 1/. 0e LUCA BY mnu/ M E==i i========mu ATTORNEK UnitedStates Patent 3,340,752 PHASING TOOL.

William V. Carney, Brooklyn, and Paul V. De Luca, .Port Washington,N.Y., assignors to Markite Corporation, New York, N.Y.

Filed Dec. 28, 1965, Ser. No. 516,983 2 Claims. (Cl. 81-90) Thisinvention relates to phasing tools for servo mounted components ingeneral and more particularly to means for phasing a servo componentafter it has been placed in the system.

' A problem has existed in the phasing of servo mounted components.Servo mounting is a particular type of installation wherein theinstrument housing is placed in an aperture in the panel. Fasteningmeans such as screws threadably engaged in the panel cooperate withmembers arranged to fit in an annular groove in the instrument housing.A servo mounting is differentiated from another common type wherein themounting screws pass through clearance holes in the panel and arethreadably engaged in the instrument housing. It has often been foundnecessary after installation to phase a gang of conventionalotentiometers with respect to a shaft in the mechanical system. Sincethe technician was unable to otherwise get at the potentiometer case,prior to the present invention, it was the practice to loosen themounting dogs slightly and then hit the rear cover of the potentiometerwith a hammer and screwdriver. Because of this mishandling, theindividual potentiometers' in the gang were often moved out of phasewith each other.

The present invention provides a very simple, low cost, yet effectivesolution to this problem. For illustrative purposes only, potentiometerswill be described but it should be clearly understood that the inventionis not limited thereto. The invention may, in fact, be practiced withany servo mounted component that requires phasing after it is placed inthe system.

In one of the embodiments illustrated, a gear tooth form or knurl isformed on the front cover or housing of the potentiometer. A hollowpinion is placed over one of the screw heads holding the mounting dogsin place, the pinion being arranged to mesh with the housing gear suchthat the potentiometer housing is angularly displaced when the pinion ismanually rotated. Since the gear on the potentiometer housing is locatedon the front cover, the external phasing procedure does not disrupt thecup-tocup phasing relationship of a multigang potentiometer.

In another embodiment a hole in the panel is utilized to receive a pinhaving a coaxial gear and handle. In this instance the dogs are loosenedbut are not used for piloting. The pin on the tool serves this functionto permit the coaxial gear to mesh with a gear formed on the instrumenthousing. Rotation of the tool handle causes rotation of the meshinggears and phasing of the instrument.

Accordingly, it is an object of this invention to provide improved lowcost phasing means for a servo mounted component.

Another object is to provide an improved servo housing having phasingmeans integral therewith.

An additional object is to provide a simple phasing tool that willcooperate with the aforementioned housing.

A particular object is to provide an improved servo housing havingintegral phasing means that may be frictionally rotated by means of amating phasing tool.

Still another object is to provide a phasing tool for the aforementionedhousing that cooperates with the mounting means of the servo component.

These and other features, objects and advantages of the invention will,in part, be pointed out with particularity and will, in part, becomeobvious from the following more 3,3401,75Z Patented Sept. 12, 1967detailed description of the invention taken in conjunction with theaccompanying drawing which forms an integral part thereof.

In the various figures of the drawing, like reference charactersdesignate like parts.

In the drawing:

FIG. 1 is an exploded, perspective view of a typical servo componenttogether with thephasing means of the present invention;

FIG. 2 is an elevational view illustrating the servo component of FIG. 1secured to a mounting panel;

FIG. 3 is an enlarged, fragmentary elevational View showing the phasingtool in operation;

FIG. 4 illustrates in elevation an alternative embodiment of the presentinvention; and

FIG. 5 is a side elevational view, partly in section, of anotheralernative embodiment.

Referring now to FIG. 1 of the drawing, servo component 10 is amulti-unit ganged potentiometer having a shaft 12 coaxially disposed inhousing 14. Cylinders 16 together with a rear cover 18 and a front cover20 comprise a unitary housing. Terminals 22 integrally mounted on eachcylindrical housing portion 16 are electrically connected to internal,conventional potentiometer elements and are adapted to be connected toan external utilization device.

Front cover 20 is provided with a first piloting diameter 24 which isdisposed in an appropriately sized aperture 26 in mounting panel 28. Anannular groove 30 formed in the front cover receives clamping dogs 32that secure the potentiometer to the panel by means of screws 34. Justrearward of groove 30 there is formed a gear tooth form 36. It should benoted that while a fairly accurate gear tooth has been illustrated, itis not absolutely essential. A knurl, shown as 36a in FIG. 4, willproduce sufliciently deep and evenly spaced ridges to be a reliablesubstitute for the gear teeth. It should also be appreciated that eitherthe gear or knurl need not be continuous. A small segment of either inthe area of a clamping dog is all that is required since rotation of theinstrument housing for phasing purposes is not usually too extensive.

Phasing tool 40 is comprised of a hollow member 42 having gear teeth 44formed at one end 46. A knurled surface 44a (FIG. 4) may be substitutedfor the gear form. To utilize the phasing tool, screws 34 are firstslightly loosened and then tool end 46 is piloted on one of the screwheads so that gears 36 and 44 are in mesh. Rotation of the tool aboutthe screw axis causes rotation of the potentiometer housing about itscentral shaft. However, the cup-to-cup relationship in a gangedpotentiometer is not disturbed because the internal potentiometercompenents are secured to their respective cases; the cases and endcovers are an integral unit and it is the front end cover that isrotated by the phasing tool.

The force required to phase the potentiometer is derived from thecoeflicients of friction between the material of the front cover and themating diameter of the mounting panel. To minimize the force required,it is contemplated that a low coefiicient of friction plating materialbe utilized on the potentiometer case. Teflon-impregnated anodizing onaluminum is an example of a suitable mater1a The phasing tool has beenshown to be cylindrical so that a simple screwdriver 48 can fittherethrough. This serves to support the phasing tool while it is beingrotated and in addition permits tightening down on the screw afterphasing is accomplished without having to remove the tool. It should beevident, however, that the phasing tool may have a solid body portionwith only a cupshaped end about which is formed the pinion. The cup needonly be deep enough to freely accommodate the screw head.

An alternative embodiment of the invention is illustrated in FIG. 5. Aninstrument 50, of the type requiring phasing, is mounted in panel 52 bymeans of clamping dogs 54. Only one clamp is shown, the other being onthe opposite side of the instrument 180 away. The clamping arrangementis, of course, but one of several that may be employed. However, incontrast to the previous embodiments the mounting screws herein are notutilized for piloting the phasing tool. Gear 56 is formed on the frontcover of the instrument housing proximate the mounting panel.

Phasing tool 58 is comprised of an elongated handle 60 and a gear 62 atone end thereof. Extending coaxially from the face of the gear is apiloting pin 64. As shown in the drawing, pin 64 is adapted to 'bereceived in an aperture 66 in the panel. The aperture is located closeto the instrument so that when the tool is inserted gears 56 and 62 willmesh. If the clamping dogs are first loosened, then rotation of the toolwill phase the instrument. As noted in the previous embodiments, themating surfaces both driving and driven need not be completely circular.As a matter of fact, only a single notch on the instrument periphery anda single tooth on the tool will provide suflicient angular movement ofthe instrument for most applications. It is also practical, and may evenbe desirable from an appearance point of view, to form aperture 66 as arecess that does not go completely through the panel but which is deepenough to receive pin 64.

There has been disclosed heretofore the best embodiment of the inventionpresently contemplated and it is to be understood that various changesand modifications may be made by those skilled in the art withoutdeparting from the spirt of the invention.

What is claimed is:

1. The combination, with a servo mounted instrument having a housingreleasably secured to a panel by means of clamps and screws and a shaftdisposed in the housing to define a longitudinal axis, of:

(a) a driven surface formed on the outside of the instrument housing;

5 (b) an elongated, rotatable tool having a longitudinal axis, saidtool, in operation, being rotatable about an axis parallel to thehousing axis;

(0) a coaxial driving surface formed integrally at one end of said tool;and

(d) coaxial piloting means formed integrally with said driving surface,wherein said piloting means is an opening in the end of said toolproximate said driving surface, said opening being at least as large asthe diameter of the head of one of said screws, said driving and drivensurfaces being in meshing engage- 504,668 12/1954 Italy.

OTHER REFERENCES 1960 Resolver Handbook, Reeves Instrument Corp.,Roosevelt Field, Garden City, N.Y., pages 22 and 23.

WILLIAM FELDMAN, Primary Examiner. G. WEIDENFELD, Assistant Examiner.

1. THE COMBINATION, WITH A SERVO MOUNTED INSTRUMENT HAVING A HOUSINGRELEASABLY SECURED TO A PANEL BY MEANS OF CLAMPS AND SCREWS AND A SHAFTDISPOSED IN THE HOUSING TO DEFINE A LONGITUDINAL AXIS, OF: (A) A DRIVENSURFACE FORMED ON THE OUTSIDE OF THE INSTRUMENT HOUSING; (B) ANELONGATED, ROTATABLE TOOL HAVING A LONGITUDINAL AXIS, SAID TOOL, INOPERATION, BEING ROTATABLE ABOUT AN AXIS PARALLEL TO THE HOUSING AXIS;